Paul, an apostle of Jesus Christ
The apostle puts his name to this epistle, by which he was known in the Gentile world, as he usually does in all his epistles; and styles himself "an apostle", as he was, having seen Christ in person, and received his commission, doctrine, and qualifications immediately from him, with a power of doing miracles to confirm the truth of his mission. This he chose to make mention of, partly because the false teachers everywhere insinuated that he was not an apostle; and partly to give the greater sanction and authority, and command the greater regard and credit to what he should say; as well as to excuse his freedom in writing to them whom he had never seen, since he was an apostle of the Gentiles, and so to them; see ( Romans 11:13 ) ( 1 Timothy 2:7 ) ( 2 Timothy 1:11 ) ; he calls himself an apostle "of Jesus Christ"; not of men, he was not sent out by men, but by Christ, who appeared to him, made him a minister of his, gave him his Gospel by revelation, abundantly qualified him for the work, sent him forth unto the Gentiles, in whose name he went as an ambassador and messenger of his, and whom he preached, and by whom he was greatly succeeded, to the conversion of many souls, who were seals of his apostleship in every place, ( 1 Corinthians 9:2 ) : into which office he came
by the will of God;
not by the will of men, for he derived no authority and power, nor received any doctrine from men; nor by his own will, of his own head, by any usurpation of his; he did not take this office upon him of himself, but was invested with it, according to the secret will and purpose of God, from everlasting, who had ordained and appointed him to this service, and according to his will of command made known to him in time, when he told him what he should do, and openly separated, and sent him forth to do the work he had called him to; and which arose not from any merits or worthiness of the apostle, but from the sovereign good will and pleasure, free grace and favour, of God, to which the apostle continually ascribes it in all his epistles:
and Timotheus [our] brother;
who joined with the apostle in this epistle, and whom he calls a "brother"; partly because of the Christian relation he stood in to him, and them, they being all brethren, children of the same Father, partakers of the same grace of regeneration, belonging to the same family, and so should own and love one another as brethren; and partly and chiefly because of his being a brother, companion, fellow soldier, and a fellow labourer in the Gospel. He mentions him, either because he was known unto them, or that he might be so; and to show the agreement there was between them in the doctrine of Christ, which might have the greater weight with them to abide in it.